Instead of automatically creating a user account entry for any user
executing a command, we use an Account enum which covers both
registered and "transient" unregistered users. If a user registers,
the context has the actual user instance available, with state and
everything. If a user is unregistered, then the account is considered
transient for the request, with only the username available.
- Adds a user_state table, currently only with active_room.
- A user must have an account to take advantage of state.
- Now, all users will get an 'account' even if they don't explicitly register.
- Bonus: converts user queries to compile-time checked macros.
To support these automatically created "accounts," the accounts table
now also has an account_status column, indicating if the user is
registered or not (or pending activation--future use).
The User model has been updated with extra properties from the state,
and the user is now carrried in the Context during command execution.
A user is ensured to be created before executing the command.
Add get/insert functions for RoomInfo in the rooms db.
Move 'bot joins room' code to single method, so we can also record a
RoomInfo struct into the database.